U.S. patent application number 16/487235 was filed with the patent office on 2021-05-06 for connection establishment of a terminal over a relay node in a wireless communication system.
The applicant listed for this patent is SONY MOBILE COMMUNICATIONS INC.. Invention is credited to Anders BERGGREN, Lars NORD.
Application Number | 20210136655 16/487235 |
Document ID | / |
Family ID | 1000005348329 |
Filed Date | 2021-05-06 |
![](/patent/app/20210136655/US20210136655A1-20210506\US20210136655A1-2021050)
United States Patent
Application |
20210136655 |
Kind Code |
A1 |
BERGGREN; Anders ; et
al. |
May 6, 2021 |
CONNECTION ESTABLISHMENT OF A TERMINAL OVER A RELAY NODE IN A
WIRELESS COMMUNICATION SYSTEM
Abstract
A method carried out in a terminal (100) for setting up a
connection with a wireless communication network including a
network node (10), comprising transmitting terminal preference data
(51) to the radio network, said terminal preference data indicating
terminal preference to receive one of direct or indirect downlink
transmission when the terminal (100) operates over a relay in the
uplink; transmitting a service request (54) to the network node
(10) over a relay (200); receiving information (57) from the
network node (10) indicating direct or indirect downlink data
transmission; receiving resource data (58) for a connection
configured according to said information.
Inventors: |
BERGGREN; Anders; (Lund,
SE) ; NORD; Lars; (Lund, SE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SONY MOBILE COMMUNICATIONS INC. |
Tokyo |
|
JP |
|
|
Family ID: |
1000005348329 |
Appl. No.: |
16/487235 |
Filed: |
March 12, 2018 |
PCT Filed: |
March 12, 2018 |
PCT NO: |
PCT/EP2018/056088 |
371 Date: |
August 20, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W 28/0226 20130101;
H04W 40/24 20130101 |
International
Class: |
H04W 40/24 20060101
H04W040/24; H04W 28/02 20060101 H04W028/02 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 10, 2017 |
EP |
17160243.6 |
Claims
1. A method carried out in a terminal for setting up a connection
with a wireless communication network including a network node,
comprising transmitting terminal preference data to the radio
network, said terminal preference data indicating terminal
preference to receive one of direct or indirect downlink
transmission when the terminal operates or intends to operate over
a relay in the uplink; transmitting a service request to the
network node over a relay; receiving information from the network
node indicating direct or indirect downlink data transmission;
receiving resource data for a connection configured according to
said information.
2. The method of claim 1, wherein said terminal preference data
indicates preference of direct or indirect downlink transmission
associated with one or more of system information, paging, and
downlink data.
3. The method of claim 1, wherein transmission of the service
request is triggered by the terminal preparing to send data.
4. The method of claim 1, wherein transmission of the service
request is triggered by receiving downlink paging from the
network.
5. The method of claim 1, wherein said terminal preference data is
transmitted in a Non Access Stratum procedure.
6. The method of claim 1, wherein said terminal preference data is
transmitted in radio control signaling.
7. The method of claim 1, comprising transmitting an in-coverage
indicator to the network, indicating whether the terminal is in or
out of downlink coverage dependent on signal quality detected from
said network node.
8. A method carried out in a wireless communication network
including a network node for setting up a connection with a
terminal, comprising receiving terminal preference data, said
terminal preference data indicating terminal preference to receive
one of direct or indirect downlink transmission when the terminal
operates or intends to operate over a relay in the uplink;
receiving a service request from the terminal over a relay;
transmitting information to the terminal, indicating direct or
indirect downlink data transmission; transmitting resource data for
a connection configured according to said information.
9. The method of claim 8, wherein said terminal preference data
indicates preference of direct or indirect downlink transmission
associated with one or more of system information, paging, and
downlink data.
10. The method of claim 8, wherein said service request is
triggered by the terminal preparing to send data.
11. The method of claim 8, comprising transmitting a paging message
to the terminal from the network node responsive to receiving a
paging request from a core network, wherein said service request is
triggered by said paging message.
12. The method of claim 11, comprising transmitting said paging
message in accordance with said terminal preference data.
13. The method of claim 8, wherein said terminal preference data is
received in a Non Access stratum procedure by the terminal.
14. The method of claim 8, wherein said terminal preference data is
received from the terminal in radio control signaling.
15. The method of claim 8, wherein said information is determined
based on at least radio traffic data detected in the network node,
with said terminal preference data as preference.
16. The method of claim 8, comprising receiving an in-coverage
indicator from the terminal, associated with signal quality
detected from said network node by the terminal.
17. The method of claim 16, wherein said in-coverage indicator is
received in a terminal-initiated service request procedure.
18. The method of claim 16, wherein said information indicates
indirect downlink data transmission responsive to said in-coverage
indicator indicating that the terminal is out of coverage from the
network node.
19. A method for bearer modification for a terminal in connected
mode communication with a network node of a wireless communication
network, wherein the terminal is configured with an indirect uplink
connection via a relay and a direct downlink connection from the
network node, comprising measuring signal quality of downlink data
from the network node in the terminal; transmitting a signal
quality measurement to the network node; transmitting an
in-coverage indicator, indicating out of coverage, based on the
detected signal quality; receiving bearer modification data of an
indirect downlink connection from the network node, responsive to
transmitting said in-coverage indicator.
Description
TECHNICAL FIELD
[0001] This disclosure relates to methods and devices for use in a
radio communication system, in which a connection is established or
modified between a terminal and a network node of a wireless
communication network. Specifically, presented solutions are
related to scenarios which involve relaying information or data
over a relay node, between the terminal and the network node.
BACKGROUND
[0002] Third and fourth generation mobile telecommunication
systems, such as those based on the 3GPP defined UMTS and Long Term
Evolution (LTE) architecture are able to support more sophisticated
services than simple voice and messaging services offered by
previous generations of mobile telecommunication systems. For
example, with the improved radio interface and enhanced data rates
provided by LTE systems, a user is able to enjoy high data rate
applications such as mobile video streaming and mobile video
conferencing that would previously only have been available via a
fixed line data connection. The demand to deploy third and fourth
generation networks is therefore strong and the coverage area of
these networks, i.e. geographic locations where access to the
networks is possible, is expected to increase rapidly.
[0003] The widespread deployment of third and fourth generation
networks has led to the parallel development of a number of new
infrastructure architectures involving a variety of classes of
devices, of wireless access point units and of applications which
may require different data rates, coverage areas or transmission
powers. Unlike a conventional third or fourth generation
communication terminal such as a smartphone, a whole new segment of
devices has been considered, including devices which are relatively
simple and inexpensive, having a reduced capability. Examples of
recent developments include so-called machine type communication
(MTC) applications and Internet-of-Things (IoT) devices, which may
be configured as by semi-autonomous or autonomous wireless
communication devices communicating small amounts of data on a
relatively infrequent basis. Examples include so-called smart
meters which, for example, are located in a customer's house and
periodically transmit information back relating to the customers
consumption of a utility such as gas, water, electricity and so on.
Other examples may include simple sensors or meters, wearable
devices and communication devices that may be placed on any object
for tracking.
[0004] Whilst it can be convenient to have different systems
addressing different needs from different mobile network users, the
additions of new infrastructure and new services can also create an
infrastructure problem, which is not desirable in a mobile network.
There are predominantly three parameters which can be changed in
order to increase Radio Access network capacity: higher spectral
efficiency, more radio spectrum and denser cell layout. In order to
meet an expected large increase in the number of communication
devices, small cells are getting a lot of attention. However, there
are still limitations on network capacity and the geographical
areas that can be served by such networks. These limitations may,
for example, be particularly relevant in situations in which
networks are experiencing high load and high-data rate
communications between communication terminals, or when
communications between communication terminals are required but the
communication terminals may not be within the coverage area of a
network. The coverage area of Internet-of-Things (IoT) devices have
been reduced, since they are allowed to transmit with lower output
power than normal smartphones. This has created an unbalanced link
budget for these devices, the uplink coverage is less than the
downlink coverage area. In order to address these limitations, in
LTE releases-12 and -13, the ability for LTE communication
terminals to perform device-to-device (D2D) communications has been
introduced and developed.
[0005] D2D communications allow communication terminals that are in
close proximity to communicate directly with each other, both when
within and when outside of a coverage area or when the network
fails. This D2D communications ability can allow user data to be
more efficiently communicated between communication terminals by
obviating the need for user data to be relayed by a network node
such as a base station, and also allows communication terminals
that are in close proximity to communicate with one another
although they may not be within the coverage area of a network.
[0006] D2D communications may also allow a first communication
terminal to communicate with a base station via a second
communication terminal, so that the second communication terminal
acts as a relay node. This allows coverage extension when the first
communication terminal is out of coverage of the base station, for
example. Alternatively, the first communication terminal may be
within coverage of the base station but may nonetheless communicate
with the base station via the second communication terminal. In
this case, the second communication terminal can be granted the
right to manage the first communication terminal (including control
of mobility, resource allocation, etc.), and thus provides a means
for the network capacity to be increased. This may be beneficial,
e.g. for simple D2D devices, since it may provide the possibility
to limit output power on the radio transceiver, when a relay node
is closer than the serving base station, but also for a terminal
that may not support extended coverage using repetitions or which
prefers to not operate in Extended Coverage mode.
[0007] Agreements within 3GPP associated with Layer 2 Relay may be
found in TR 36.746. In November 2016 a corresponding study in SA2
started called REAR (Relay for wearable), studying system impact to
support Layer 2 relay. Result from the REAR study can be found in
TR 23.733. Layer 3 relay specified in TS 23.303, and TS 36.331 sets
the baseline for discovery or relay function and how to request and
set-up a Layer 3 relay link between the Remote terminal, or User
Equipment (UE), and Network. The relay, or relay node, acts as an
IP router and each remote terminal will be provided a unique IP
address in the local IP network that the IP router manages. The IP
data is embedded in the relay node's EPS traffic, towards the
network. To be able to perform lawful interception the relay node
needs to inform the MME of the Remote terminal's identity that the
relay is serving. Based on this information the network can then
inspect each Remote terminal's IP packets.
[0008] An open issue relates to whether to use Uni-directional or
bi-directional link towards the terminal. Uni-directional link
meaning that the downlink (DL) to the remote terminal is sent
directly from the eNB over Uu and the uplink (UL) from the remote
terminal is sent indirectly to the eNB via a relay (PC5+Uu of the
relay). Bi-directional means both DL and UL is sent via the relay
(PC5+Uu of the relay). Related to the uni-directional and
bi-directional link discussion is how to page the remote terminal
and set up a communication connection and transfer the terminal to
Connected mode. Various discussed Paging occasion options include
that the relay node, i.e. the terminal acting as a relay, monitors
relay terminal PO only (single paging occasion); that the relay
node monitors remote terminal PO (multiple paging occasions); that
the remote terminal monitors Uu (direct DL paging); and that the
relay node monitors paging occasions that are aligned between the
remote terminal and relay node PO. The third option suggests that
the DL page message is monitored directly by the remote terminal,
basically proposing a uni-directional link configuration. However,
whatever paging option is selected, it need not be suitable for a
specific remote terminal at all instances.
SUMMARY
[0009] The use of either uni- or bi-directional links may depend on
several factors, such as terminal capability, terminal preference
and Network preference. In certain radio environment, the terminal
may prefer to receive in the downlink via direct link, instead of
via a relay node. In other scenarios the terminal may prefer to
only camp on a relay node and receive all downlink information,
system information, paging, and user data transfer, via the relay
node. But in some scenarios the terminal may prefer a mix of these
different approaches, A solution is therefore proposed herein,
whereby the Remote terminal is configured to indicate preference
for using either a direct link or an In-direct link via a relay in
the downlink reception.
[0010] According to a first aspect, a method carried out in a
terminal is provided, for setting up a connection with a wireless
communication network including a network node, comprising
[0011] transmitting terminal preference data to the radio network,
said terminal preference data indicating terminal preference to
receive one of direct or indirect downlink transmission when the
terminal operates over a relay in the uplink;
[0012] transmitting a service request to the network node over a
relay;
[0013] receiving information from the network node indicating
direct or indirect downlink data transmission;
[0014] receiving resource data for a connection configured
according to said information.
[0015] Throughout this document the term Service Request includes
both the NAS message and radio control signaling in order to setup
the communication between the network and terminal.
[0016] In one embodiment, said terminal preference data indicates
preference of direct or indirect downlink transmission associated
with one or more of system information, paging, and downlink
data.
[0017] In one embodiment, transmission of the service request is
triggered by the terminal preparing to send data.
[0018] In one embodiment, transmission of the service request is
triggered by receiving downlink paging from the network.
[0019] In one embodiment, said terminal preference data is
transmitted in a Non Access Stratum procedure.
[0020] In one embodiment, terminal preference data is transmitted
in radio control signaling, e.g. RRC messages used in 3GPP.
[0021] In one embodiment, the method comprises
[0022] transmitting an in-coverage indicator to the network,
indicating whether the terminal is in or out of downlink coverage
dependent on signal quality detected from said network node.
[0023] According to a second aspect, a method carried out in a
wireless communication network is provided, including a network
node for setting up a connection with a terminal, comprising
[0024] receiving terminal preference data, said terminal preference
data indicating terminal preference to receive one of direct or
indirect downlink transmission when the terminal operates over a
relay in the uplink;
[0025] receiving a service request from the terminal over a
relay;
[0026] transmitting information to the terminal, indicating direct
or indirect downlink data transmission;
[0027] transmitting resource data for a connection configured
according to said information.
[0028] In one embodiment, terminal preference data indicates
preference of direct or indirect downlink transmission associated
with one or more of system information, paging, and downlink
data.
[0029] In one embodiment, said service request is triggered by the
terminal preparing to send data.
[0030] In one embodiment, the method comprises
[0031] transmitting a paging message to the terminal from the
network node responsive to receiving a paging request from a core
network, wherein said service request is triggered by said paging
message. The paging request may include the terminal preference to
receive the paging message via direct or indirect downlink
transmission.
[0032] In one embodiment, the method comprises
[0033] transmitting said paging message in accordance with said
terminal preference data.
[0034] In one embodiment, said terminal preference data is received
in a Non Access stratum procedure by the terminal.
[0035] In one embodiment, said terminal preference data is received
from the terminal in radio control signaling.
[0036] In one embodiment, said information is determined based on
at least radio traffic data detected in the network node, with said
terminal preference data as preference.
[0037] In one embodiment, the method comprises
[0038] receiving an in-coverage indicator from the terminal,
associated with signal quality from said network node detected by
the terminal.
[0039] In one embodiment, said in-coverage indicator is received in
a terminal-initiated service request procedure.
[0040] In one embodiment, said information indicates indirect
downlink data transmission responsive to said in-coverage indicator
indicating that the terminal is out of coverage from the network
node.
[0041] According to a third aspect, method for bearer modification
is provided for a terminal in connected mode communication with a
network node of a wireless communication network, wherein the
terminal is configured with an indirect uplink connection via a
relay and a direct downlink connection from the network node,
comprising
[0042] measuring signal quality of downlink data from the network
node in the terminal;
[0043] transmitting a signal quality measurement to the network
node;
[0044] transmitting an in-coverage indicator, indicating out of
coverage, based on the detected signal quality;
[0045] receiving bearer modification data of an indirect downlink
connection from the network node, responsive to transmitting said
in-coverage indicator.
BRIEF DESCRIPTION OF THE DRAWINGS
[0046] A more complete appreciation of the disclosure and
advantages thereof will be readily obtained as the same becomes
better understood by reference to the following detailed
description when considered in connection with the accompanying
drawings, wherein like reference numerals designate identical or
corresponding parts throughout the several views, and wherein:
[0047] FIG. 1 schematically illustrates a relay scenario for a
terminal in a wireless communication system;
[0048] FIG. 2 schematically illustrates UL and DL coverage for a
terminal with respect to a network node in a wireless communication
network of the radio communication system;
[0049] FIG. 3 illustrates an embodiment of a method carried out in
a terminal according to various embodiments;
[0050] FIG. 4 illustrates an embodiment of a method carried out in
a network node according to various embodiments;
[0051] FIG. 5 schematically illustrates steps and signals conveyed
in various embodiments, where connection setup is triggered by a
terminal;
[0052] FIG. 6 schematically illustrates steps and signals conveyed
in various embodiments, where connection setup is triggered by the
network;
[0053] FIG. 7 schematically illustrates steps and signals conveyed
in various embodiments, related to bearer modification in connected
mode over a relay node;
[0054] FIG. 8 schematically illustrates elements included in a
terminal configured in accordance with an embodiment; and
[0055] FIG. 9 schematically illustrate elements included in a
network node configured in accordance with various embodiments.
DETAILED DESCRIPTION
[0056] Hereinafter preferred embodiments of the present technique
will be described in detail with reference to the appended
drawings. Note that, in this specification and appended drawings,
structural elements that have substantially the same function and
structure are denoted with the same reference numerals, and
repeated explanation of these structural elements is omitted.
[0057] FIG. 1 provides a schematic diagram of a wireless
communication system, in which a wireless communication network
includes a core network 1 and at least one network node 10, such as
an access node. The network node may also be referred to as a base
station and may e.g. be an enhanced Node B (eNodeB or eNB) of an
LTE network or a gNB of a 5G network. An access node provides a
wireless access interface to the one or more communication
terminals 100, 200 within a coverage area or cell 11. The wireless
communication system may thus be referred to as a cellular
telecommunications system, which typically operates by radio
communication.
[0058] Herein, communication terminals of the wireless
communication system are referred to as terminals 10, 200 for
short. In a 3GPP wireless communication system, such terminals 100,
200 may be referred to as User Equipment, UE. The terminals 100,
200 may communicate messages, control data and user data via the
transmission and reception of signals representing data using the
wireless access interface. The network node 10 is communicatively
linked to core network components, illustrated in the drawing by
one representative network element 1, such as a serving gateway
support node and an external network, which may be connected to one
or more other communications systems or networks. The terminals
100, 200 are configured to communicate with one or more other
communication terminals served by the same or a different coverage
area via the network node 10, or with servers or other entities
outside the communication network. Communication in the direction
from the network node 10 to the terminals 100, 200 is referred to
as downlink communication, whereas communications from the
terminals 100, 200 to the network node 10 is referred to uplink
communication.
[0059] Although cellular communications system such as those based
on the previously released LTE standards have been commercially
successful, a number of disadvantages are associated with such
centralized systems. For example, if two terminals which are in
close proximity wish to communicate with each other, uplink and
downlink resources sufficient to convey the data are required.
Consequently, two portions of the system's resources are being used
to convey a single portion of data. This limitation may be
problematic when the system is experiencing high load or base
station coverage is not available, for instance in remote areas.
Overcoming these limitations may increase both the capacity and
efficiency of LTE networks but also lead to the creations of new
revenue possibilities for LTE network operators. D2D communications
offer the possibility to address the aforementioned problems of
network capacity and the requirement of network coverage for
communications between terminals.
[0060] As previously discussed, D2D communications may also allow a
first terminal 100 to communicate with a network node 10 via a
second terminal 200, wherein the second terminal 200 acts as a
relay node. This allows coverage extension when the first terminal
100 is out of coverage of the base station, for example.
Alternatively, the first terminal 100 may be within coverage of the
network node 10 but may nonetheless communicate with the network
node 10 via the second terminal 200.
[0061] With reference to FIGS. 1 and 2, various D2D terminals 100,
such as small IoT/wearable devices, which may e.g. be configured to
operate under the specifications associated with NB-IoT or eMTC,
may be allowed to have a relaxed Transmitter performance. In such a
case, the link budget for UL and DL will become unsymmetrical. The
terminal 100 will be able to receive DL data/info in the coverage
area 11B of the entire cell, but only transmit UL data in a smaller
area 11A closer to the network node 10. This represents one example
where a terminal 100 may have different preferences for
communication with the network, i.e. where an operator has a
network deployment where the UL coverage is much smaller than the
DL coverage.
[0062] On a general level, solutions are proposed herein for a
remote terminal to dynamically indicate its preference the network,
such as to a network node 10 and a Mobile Management Entity (MME)
of a core network 1, related to how the terminal 100 prefers to
receive downlink data and information in a relay situation. On the
one hand, a terminal 100 may be configured with preference for
direct downlink reception of certain signals over a Uu link from a
network node 10, as indicated by the full-drawn arrow in FIG. 1,
whereas the terminal 100 may be configured with preference for
indirect downlink reception of other signals over a PC5 link from
the network node 10, via a relay node 200, as represented by the
dashed arrow.
[0063] A terminal 100 is configured to receive system information
and to listen for paging in idle mode and is configured to receive
data in the downlink and transmit data in the uplink in connected
mode. In various embodiments, the indication of preference is
related to one or more of the following DL areas: [0064] System
information (Direct/In-direct) [0065] Paging (Direct/In-direct)
[0066] Connected mode downlink data transfer (Direct/In-direct)
[0067] This downlink preference may be indicated to the network by
means of terminal preference data, which provides an indication
related to on or more of the aforementioned DL scenarios. In
various embodiments, the terminal preference data may be provided
to the network 1, 10 by the terminal 100. Providing the data to the
network may be accomplished in an attach procedure, i.e. when the
terminal 100 first communicates with the network to establish its
part of the wireless communication system, e.g. by including the
terminal preference data in Capability signaling. In an attach
message, the terminal 100 may e.g. indicate its capability to
support either or both unidirectional and bidirectional mode.
Capability signaling may also include an indication of preference
to always receive downlink direct while using a relay for the
uplink (preference=unidirectional, could be e.g. bitmapped
"001").
[0068] Terminal preference data may additionally, or alternatively,
be transmitted in accordance with a predetermined schedule or
repetition cycle, or when the terminal 100 makes an update
transmission to the network, e.g. when reporting network node
signal quality measurements to the network, during association to a
relay node 200, or dynamically with RRC signaling upon connection
establishment or modification when conditions are changing. In one
embodiment, the terminal preference data may include an
identification of a type or class of terminal, tied to a specified
default selection of preference related to direct or indirect DL
transmission, rather than the specific indication of preference. In
such an embodiment, the network may ascertain downlink preference
for a specific terminal 100 from stored preference data, e.g.
determined by specification or by terms of a subscription to an
operator of the wireless communication system, which stored data is
accessible using the identification received in terminal preference
data from the terminal 100.
[0069] Additionally, the terminal may in various embodiments be
configured to set, and transmit to the network, an in-coverage
indicator, providing the terminal's indication of whether the
terminal 100 is In or Out of DL coverage with the network node 10
on which the terminal 100 is camping. Such a coverage indicator may
e.g. be a binary indicator, such as a code or flag, which may be
transmitted as a message, indicating yes or no.
[0070] The terminal preference indicator in accordance with the
examples above is only valid in case of use of relay, where uplink
traffic (signaling and data) is transmitted via the relay node 200.
In other words, the relay node is at least used in the uplink.
Based on connected mode measurement reporting, the network node 10
may also handle possible change between direct (unidirectional) and
indirect (bidirectional) link and vice versa. In the end it may be
to the network, such as the access node 10 or a node 1 of the core
network to make the decision about setting up and changing link,
based on explicit indication, earlier provided preferences and
measurement reports from the terminal 100.
[0071] A first general embodiment will now be described with
reference to FIG. 3, representing steps carried out in a terminal
100 which communicates with a network node 10 of a wireless
communication network. Furthermore, the remote terminal 100 is
associated with a relay node 200, at least for uplink
communication. The method broadly relates to a method carried out
in the terminal 100 for setting up a connection with the wireless
communication network including the network node 10, such as an
access node.
[0072] In a step S310, the terminal is configured to transmit
terminal preference data to the wireless communication network,
through the network node 10, possibly for further communication to
a core network node 1. The terminal preference data indicates
preference of one of direct or indirect downlink transmission to
apply in cases when the terminal operates over relay in the uplink
or before the uplink connection is established. The terminal
preference data may indicate the preference explicitly, e.g. by
means of a particular code which is associated to a selection of
direct or indirect connection. Alternatively, the terminal
preference data may indicate the preference implicitly, by means of
an indicator identifying the terminal 100, which is associated with
a stored preference, accessible by the network. The terminal
preference data may be transmitted in a Non Access stratum
procedure, such as attach or TAU for 4G, or initial registration or
re-registration in 5G. In another embodiment, the terminal
preference data may be transmitted in a RRC signaling.
[0073] In step S320, the terminal 100 is configured to transmit a
service request to the network over a relay node 200, whereby the
terminal initiates a service request procedure with the network
node 10. While the terminal initiates the service request
procedure, it may be triggered by different causes. In one
scenario, initiation of the service request is triggered by the
terminal preparing to send data. In another scenario, initiation is
triggered by receiving downlink paging from the network. The
terminal 100 is configured to detect the trigger, so as to initiate
the service request procedure with the network. In various
embodiments, the terminal 100 may be configured to determine its
coverage status in the downlink, based on measured signal quality
on signals received from the network node 10. The terminal 100 may
further be configured to set an in-coverage indicator dependent on
the detected signal quality from said network node 10, or even
based on absence of a received signal. The terminal may be
configured to transmit the in-coverage indicator to the network
node 10, e.g. in said service request procedure. In one embodiment,
the network node may be configured to provide said information to
indicate indirect downlink data transmission, responsive to said
in-coverage indicator indicating that the terminal 100 is out of
coverage from the network node 10. This decision may thus override
the preference as indicated in the terminal preference data.
[0074] In step S330, the terminal is configured to receive
information from the network node 10, indicating direct or indirect
downlink data transmission. The network will preferably be in
control of whether indirect or direct downlink communication is to
be established. However, in preferred embodiments, the network may
take the preference as indicated by the terminal preference data be
taken into consideration. The information, indicating direct or
indirect downlink data transmission, is preferably determined in
the network based on at least radio traffic data detected in the
network node 10, but where said terminal preference data is used as
preference. As an example, unless the detected traffic in the cell
of the network node is deemed to exceed a certain level, the
network node 10 may e.g. be configured to provide said information
to acknowledge, or specifically indicate, use of the preferred
downlink connection option as indicated by the terminal preference
data. In an alternative embodiment, the information sent by the
network node 10 may be configured to specify direct or indirect
connection in the downlink only if a decision is taken in the
network node 10 to not follow the terminal preference. A decision
related to the particular downlink connection may be taken based on
a collective traffic situation in the cell, as caused by all
terminals camping on the network node 10.
[0075] In step S340, the terminal may be configured to receive
resource data for a connection configured according to the
information. This step may conclude the establishment of a
connection for data communication, i.e. a transition to connected
mode of the terminal.
[0076] A second general embodiment will now be described with
reference to FIG. 4, representing steps carried out in a network
node 10, which may be or include an access node, which communicates
with a terminal 100 of a wireless communication network.
Furthermore, the remote terminal 100 is associated with a relay
node 200, at least for uplink communication. The method broadly
relates to a method carried out in the network, such as in a
network node which may be or include an access node, for setting up
a connection with the terminal 100.
[0077] In a step S410, the network is configured to receive
terminal preference data from the terminal. The terminal preference
data indicates preference of one of direct or indirect downlink
transmission when the terminal operates over relay in the uplink.
As described with reference to FIG. 3, which is relevant also for
the embodiment of FIG. 4, the terminal preference data may indicate
the preference explicitly or implicitly. Examples given with
reference to FIG. 3 are equally applicable to the embodiment of
FIG. 4.
[0078] In step S420, the network, such as the network node 10, is
configured to receive a service request to the network over a relay
node 200, as caused by the terminal initiating a service request
procedure with the network node 10. While the terminal initiates
the service request procedure, it may be triggered by different
causes, as outlined with reference to FIG. 3, which are applicable
to the embodiment of FIG. 4 too.
[0079] In step S430, the network node 10 is configured to transmit
information to the terminal 100, indicating direct or indirect
downlink data transmission. The network will preferably be in
control of whether indirect or direct downlink communication is to
be established. However, in preferred embodiments, the network may
take the preference as indicated by the terminal preference data be
taken into consideration. The information, indicating direct or
indirect downlink data transmission, is preferably determined in
the network based on at least radio traffic data detected in the
network node 10, but where said terminal preference data is used as
preference. Examples provided for the embodiment of FIG. 3 are
equally applicable to the embodiment of FIG. 4.
[0080] In step S440, the network node 10 may be configured to
transmit resource data for a connection configured according to the
information, to the terminal 100. This step may conclude the
establishment of a connection for data communication, i.e. a
transition to connected mode of the terminal.
[0081] FIG. 5 schematically illustrates an exemplary embodiment of
a method for setting up a connection between a terminal 100 and a
wireless communication network including a network node 10, which
falls within the scope of the general embodiments of FIGS. 3 and 4.
The drawing indicates steps carried out by the terminal 100 and the
network node 10, as well as signaling between these entities and
also a relay node 200. It should be understood that not all steps
or tasks required for setting up a connection may be illustrated.
The actual process of setting up a connection over a relay,
including detection and association with a relay, may as such be
carried out as already provided in e.g. R12/R13 D2D as
identified.
[0082] As indicated in the drawing, the terminal 100 is configured
to provide terminal preference data 51 to the network 10. As noted,
this may be accomplished in various ways, such as at initial
attach, where the terminal 100 may signal capability of supporting
both unidirectional and bi-directional mode when using a relay. The
terminal preference data 51 may, in addition to, or alternatively,
be provided in later signaling, and may then be accomplished by
uplink transmission over a relay 200. In a first example, the
terminal preference data may specify the terminal presence for
downlink data as: System information=in-direct, paging=in-direct,
connected=in-direct. In a second example, the terminal preference
data may specify the terminal presence for downlink data as: System
information=direct, paging=direct, connected=in-direct. The
embodiment of FIG. 5 illustrates the second example.
[0083] While no cause for setting up a connection has occurred, the
terminal 100 remains in idle mode, listening to direct downlink
system information 52, as provided by the terminal preference data
51.
[0084] At a step 53, a cause or trigger to set up a connection to
the network 10 occurs in the terminal 100. In the given example,
the trigger may be that the terminal has data destined or scheduled
to be transmitted in the uplink, such as a periodic Tracking Area
Update, TAU or a timer. The terminal 100 thereby initiates a
service request procedure.
[0085] Based on estimated uplink conditions, e.g. determined by the
terminal 100 based on detected downlink conditions, the terminal
100 sends a service request 54 via the relay node 200 to the
network 10. In a preferred embodiment, the service request, or a
message included in the service request procedure, may include an
in-coverage indicator 55, where the in-coverage indicator 55 is
configured by the terminal 100 to indicate In-coverage. Note that
the in-coverage indicator has the benefit of preventing the network
from selecting direct downlink data connection (terminal preference
was earlier set to direct mode for downlink data) if the terminal
100 is Out-of-coverage. In other words, had the terminal 100
determined that downlink reception from the network node 10 was
poor, the in-coverage indicator would be set to indicate
Out-of-coverage. In such a scenario, the network 10 would be
configured, based on reception of the in-coverage indicator, to
decide to override the preference of in-direct downlink data
transmission.
[0086] In the Service request procedure, both uplink and downlink
signaling is done via the relay node 200. In this process, a
decision step 56 is carried out in the network, such as in the
network node 10, whether the downlink data traffic will be
transmitted via direct link or via indirect link. This decision is
preferably made by the network node 10, but is based on the
terminal preferences as indicated by the terminal preference data
51, and also based on network node 10 preferences taking a wider
system perspective into account. This decision may thus be taken
based on the preference indication provided in the terminal
preference data 51, and possibly even with a target to follow the
preference of the terminal. However, consideration may also be made
to e.g. the overall traffic situation in the cell of the network
node, the connection quality or data traffic communication out with
respect to the relay node 200, and other factors.
[0087] Information 57 identifying the decision taken in step 56, as
to whether an in-direct or direct link will be provided for the
connected mode, is transmitted to the terminal 100. Furthermore,
resource data 58 for the data connection, configured according to
the received information, is transmitted to the terminal 100. While
the information 57 related to type of downlink connection, and the
resource data 58, are indicated at a common downlink transmission,
it may be noted that these pieces of information may be conveyed in
separate messages.
[0088] Once the connection is setup to place the terminal 100 in
connected mode, in downlink data 59A, if any, may be transmitted
from the network node 10 to the terminal 100 over the relay 200.
Furthermore, the terminal 100 may transmit its data in the uplink
over the relay 200. It may be noted that in an alternative
embodiment, connection setup control signaling may be carried out
using a direct link in both uplink and downlink, to set up an
uplink data connection.
[0089] FIG. 6 schematically illustrates an exemplary embodiment of
a method for setting up a connection between a terminal 100 and a
wireless communication network including a network node 10, which
falls within the scope of the general embodiments of FIGS. 3 and 4.
This drawing illustrates a variant of the embodiment of FIG. 5, and
the description related to that embodiment, such as various
examples, are equally applicable to this embodiment. Again, various
steps or tasks required for setting up a connection, including
detection and association with a relay, may as such be carried out
as already provided in e.g. R12/R13 D2D as identified.
[0090] The terminal 100 is configured to provide terminal
preference data 61 to the network 10. This may be accomplished in
various ways, as provided above. In one example, the terminal
preference data may specify the terminal presence for downlink data
as: System information=direct, paging=direct,
connected=in-direct.
[0091] While no cause for setting up a connection has occurred, the
terminal 100 remains in idle mode, listening to direct downlink
system information 62, as provided by the terminal preference data
61.
[0092] In the scenario of FIG. 6, a trigger for setting up a
connection is a paging message 63, transmitted from the network
node 10 to the terminal 100. In accordance with the terminal
preference data 61, the paging message is received in direct
downlink.
[0093] Responsive to receipt of the paging message 63, the terminal
100 initiates a service request procedure. Based on uplink
conditions, the terminal 100 sends a service request 64 via the
relay node 200 to the network 10. In a preferred embodiment, the
service request, or a message included in the service request
procedure, may include an in-coverage indicator 65, where the
in-coverage indicator 65 is configured by the terminal 100 to
indicate In-coverage.
[0094] In the Service request procedure, both uplink and downlink
signaling is done via the relay node 200. In this process, a
decision step 66 is carried out in the network, such as in the
network node 10, whether the downlink data traffic will be
transmitted via direct link or via indirect link. This decision is
preferably made by the network node 10, based on the terminal
preferences as indicated by the terminal preference data 61, and
also based on network node 10 preferences taking a wider system
perspective into account.
[0095] Information 67 identifying the decision taken in step 66, as
to whether an in-direct or direct link will be provided for the
connected mode, is transmitted to the terminal 100. Furthermore,
resource data 68 for the data connection, configured according to
the received information, is transmitted to the terminal 100. While
the information 67 related to type of downlink connection, and the
resource data 68, are indicated at a common downlink transmission,
it may be noted that these pieces of information may be conveyed in
separate messages.
[0096] Once the connection is setup to place the terminal 100 in
connected mode, downlink data 69A which caused the paging signal 63
to be sent, may be transmitted from the network node 10 to the
terminal 100 over the relay 200. Furthermore, the terminal 100 may
transmit data, if any, in the uplink over the relay 200.
[0097] FIG. 7 illustrates an embodiment which relates to a method
for bearer modification for a terminal 100 in connected mode
communication with a network node 10 of a wireless communication
network. This embodiment relates to a situation wherein the
terminal 100 is configured with an indirect uplink connection via a
relay 200, usable for transmitting data in the uplink, and a direct
downlink connection from the network node 10 for receiving
data.
[0098] In the connected mode, as the terminal 100 receives downlink
data 71, the terminal measures 72 signal quality such as the CQI of
the downlink data 71 received from the network node 10.
[0099] The measured signal quality may be evaluated 73, e.g. by
being quantified or compared with predetermined criteria, such as a
signal strength or quality threshold, which may be stored in memory
or be calculated in the terminal 100. This represents a remote
channel evaluation, carried out by the terminal 100.
[0100] The terminal 100 signals to the network node 10 to transmit
a measurement report 74 with the measured signal quality,
comprising or representing e.g. CQI/RSSI measurements. Signal
quality reporting may be configured according to legacy behavior,
with the difference that the measurement report 74 is sent over the
indirect uplink over the relay node 200. Based on the received
measurement report 74, the network node 10 evaluates 75 the
measured signal quality, to determine whether to maintain a direct
downlink, or to change to an indirect downlink. Measuring 72 and
transmitting measurement reports 74 may be repeated several times,
while the terminal 100 is receiving data in the connected mode.
[0101] In a situation where the terminal 100 is close to an edge of
the cell or coverage area 11B (FIG. 2), the signal quality of the
downlink data 71 will get weaker. This may be determined by
measuring the signal strength 72, or even concluding that data that
was expected was not received.
[0102] As the measured signal quality is evaluated 76, a control
unit in the terminal sets an in-coverage indicator to indicate
Out-of-coverage. The terminal 100 transmits the in-coverage
indicator 77 to the network node 10 over the relay node 200. This
transmission may be provided as a control signal, e.g. in RRC
signaling. Upon detecting 78 that the received in-coverage
indicator 77 indicates Out-of-coverage, the network node transmits
radio bearer modification data 79 to an indirect downlink
connection from the network node, responsive to transmitting said
in-coverage indicator. Note alternatively to shown in FIG. 7 the
radio bearer modification data 79 could be sent directly from
network node 10 to the terminal 100. Bearer modification is thus
obtained to bidirectional mode, over relay node 200, in both uplink
and downlink. The use of a remote evaluation of signal strength,
and reporting the in-coverage indicator 77, may be beneficial for a
terminal 100 with infrequent signal strength reporting 74, as the
terminal 100 may convey the Out-of-coverage situation as soon as
detected, and thereby trigger the network node 10 to execute bearer
modification to an indirect downlink.
[0103] FIG. 8 schematically illustrates a terminal 100 for use in a
wireless communication system, configured according to the
embodiments presented herein. The terminal 100 may e.g. an eMTC
device or a NB-IoT device, or other type of user device for radio
communication, or a component included in such a device. Obviously,
the terminal 100 may include other features and elements than those
shown in the drawing or described herein, such as at least one
antenna, power supply, and possibly a user interface etc.
[0104] The terminal 100 may be configured for communication with a
wireless communication network, such as a radio access network,
including a network node 10 such as an access node. The terminal
100 comprise a transceiver 82, such as a radio receiver and
transmitter for communicating with the network node 10 through at
least an air interface. The terminal 100 further comprises a
control unit 83 including a data memory 84, such as a non-volatile
memory, holding computer program code, and a processing device 85,
such as a microprocessor. The processing device 85 is thereby
configured to execute the computer program code from the memory 84,
wherein the control unit 83 is configured to control the terminal
100 to carry out any of the steps outlined herein for the terminal
100. In one embodiment, the control unit 83 is configured to
control the terminal 100 in a method for setting up a connection
with a wireless communication network including a network node 10,
to
[0105] transmit terminal preference data 51 to the radio network
10, said terminal preference data indicating terminal preference to
receive one of direct or indirect downlink transmission when the
terminal 100 operates over a relay in the uplink;
[0106] transmit a service request 54 to the network node 10 over a
relay node 200;
[0107] receive information 57 from the network node 10 indicating
direct or indirect downlink data transmission;
[0108] receive resource data 58 a connection configured according
to said information 57.
[0109] FIG. 9 schematically illustrates a network node 10 for use
in a wireless communication system as presented herein, and as
illustrated in FIGS. 1 and 2. As noted, the network node 20 may
e.g. be a gNB access node of a 3GPP 5G network, an eNB access node
of a 4G network, or other. The network node 10 thus may form part
of a radio access network RAN, wherein said RAN has an interface 91
to a core network 1. The network node 10 comprises a wireless
interface 92 for terminal communication, preferably by radio. The
network node 10 further includes a control unit 93 including a data
memory 94, such as a non-volatile memory, holding computer program
code, and a processing device 95, such as at least one
microprocessor, configured to execute the computer program code.
The control unit 93 is thus configured to control the network node
10 to carry out any of the steps outlined herein for the network
node 10. In one embodiment, the control unit 93 is configured to
control the network node 10 in a method for setting up a connection
with a terminal 100, to
[0110] receive terminal preference data 51, said terminal
preference data indicating terminal preference to receive one of
direct or indirect downlink transmission when the terminal 100
operates over a relay in the uplink;
[0111] receive a service request 54 from the terminal 100 over a
relay node 200;
[0112] transmitting information 73 to the terminal 100, indicating
direct or indirect downlink data transmission;
[0113] transmitting resource data 58 for a connection configured
according to said information.
[0114] Various embodiments have been disclosed herein by way of
example, to illustrate various ways of realizing methods and
devices falling within the terms of the claims. Unless where
specifically noted, these embodiments, or features related to those
embodiments, may be combined.
* * * * *